Differential gear for automotive vehicles



Oct. 15, 1935. T ADAMS 2,017,577

DIFFERENTIAL GEAR FOR AUTOMOTIVE VEHICLES Filed Nov. 1, 1934 PatentedOct. 15, 1935 QFFICE Tredgert Lee Adams, Owen Sound, Ontario, CanadaApplication November 1, 1934, 'Serial No. 750,949

4 Claims.

This invention relates to the gearing commonly provided on motorvehicles to permit of different rates of rotation of the driven wheels.It is a commonly noted weakness of such gears that there is loss oftractive effect if one wheel has less frictional grip on the roadsurface than the other and that the tractive eifect may vanishcompletely if one wheel is in contact with a slippery surface while theother has a more or less effective grip.

My object therefore is to provide means whereby the differential gearingmay be so locked, when desired, that both wheels will rotate together asif they were both rigidly secured to a common axle.

A further object is to so arrange the locking means and its controlthat, while the locking is elfected by the action of an operator, therelease is effected automatically as soon as the need for looking ispast.

I attain my object by means of a construction which may be brieflydescribed as follows.

The differential gear to which the lock is applied is of ordinary typeand is provided with two alined axles, opposed differential gearssecured thereon, a differential pinion meshing with the said gears, anda rotatable differential case or frame in which the differential pinionis journalled. A clutch member comprising a disk having a notchedperiphery is secured to or formed on the differential case and a similarclutch disk is secured to one of the axles. A clutch member is slidableon one of the said disks to and from a position to engage in the saidnotches and lock the disks together. A spring is provided tending tomove the clutch member to its engaged position. A secondspring isprovided which normally overcomes the pull of the first men- 40 tionedspring and holds the clutch in its disengaged position.

A manual control is provided whereby, at will, the action of the secondspring may be negatived and the first spring allowed to move the clutch45 to eifect the locking. After looking, if the manual control hereleased the stronger spring comes into action, but the friction on theclutch memher will hold the differential locked as long as theresistance of the axles to turning remains 50 unequal.

The invention is hereinafter more specifically described and isillustrated in the accompanying drawing in which Fig. 1 is alongitudinal section of part of a 55 differential gear provided with mylocking means;

' 6 loose on the axle 2.

Fig. 2 a cross section on the line 2-2 in Fig. 1; and

Fig. 3 a diagrammatical plan illustrating the control means.

In the drawing I illustrate such parts only of- 5 the differential of anautomotive vehicle which are necessary to the proper understanding ofthe invention.

Referring to the drawing, 1 is the differential and rear axle housingwhich as usual is a stal0 tionary part. Within this housing arepositioned the alined axles 2 to which are secured the differentialgears 3, which mesh with the diiferential pinion l which is journall'edon the differential case 5. This case at one side may be journalled' 15in the housing I in any ordinary manner. At the other side it is shownas provided with a sleeve Formed on or secured to the differential caseis a disk 1. Sleeved on the sleeve 6 is a sleeve 8 which at its outerend fits on $0 and is keyed to the axle 2. This sleeve has formed on orsecured thereto the disk 9.

The sleeve 8 is journalled in the differential housing 2 by means of thebearings [-0.

It is evident that, if the disks 1 and 9 be 25 locked together, thedifferential case will be locked to the axle carrying the disk 9 andthat both the axles 2 will of necessity rotate as a unit.

Any suitable clutch may be provided for thus locking the disks together.I show for this purpose a movable clutch member H which is slidableaxially of but is non-rotatable relative to one of the disks and isadapted to be moved to a clutching engagement with the other-disk. Themovements of this clutch member in either direction are limited byannular shoulders 21 formed on the disks 1 and 9.

A convenient arrangement is to form in the periphery of each disk aseries of transverse notches l2.

The clutch member H is ring-shaped and is provided with projections l3adapted to fit either set of notches. Normally this clutch member isengaged only with the disk I which is wider than the disk 9 but, whenmoved axially, may be engaged with both disks to form a drivingconnection between them. 1

The clutch member is formed with a peripheral groove in which fits ashifter ring I4 provided '50 J with the trunnions I5 which arejournalled in the ends of the yoke lever l6. This yoke lever is securedto the crank shaft I! journalled on the housing I and provided outsidethe housing With the crank arm l8. It is evident that by 5 rocking thecrank arm the clutch may be operated to lock or unlock the gear asdesired.

The following means are provided for actuating the crank arm I8.

A connection I9 is slidable on the crank arm l8 and may be looked asmoved by the set screw 20.

A coil spring 2| is secured at one end to the housing I or otherstationary part and at its other end to the connection i9, preferably bybeing hooked into a hole in the set screw 20.

This spring tends to rock the crank arm to lock the gear, but normallythis action is prevented by a stronger spring 22 preferably arranged asfollows.

In a suitable place convenient to the driver of the vehicle ispositioned a push button slidable in a stationary guide 24. To thisbutton is secured one end of a stout Wire 25, the other end of which issecured to the connection 19. To bring the button to a convenientposition for operation the wire may be run through a stationary guidetube 21. The spring 22 bears against the button and a stationary part 25and normally maintains the wire 25 taut and the spring 2| extended, thusholding the clutch of the gear lock disengaged. If however, the wire isslackened by pushing in the button against the pressure of the spring22, the spring 2! is left free to rock the arm l8 and engage the clutch.

As soon as the button is released the spring 22 comes into action againbut will not usually be able to retract the clutch as long as theconditions continue which rendered desirable the locking of thedifferential gear, since such conditions create a friction in the clutchwhich aids the spring 2! to overcome the action of the spring From theabove description it will be seen that I have devised simple andinexpensive means which will enable the driver of an automotive vehicleto obtain the advantage of a solid axle drive bysimply pressing a buttonand that, without further action on his part, the solid axle conditionscontinue as long as the conditions demand, after that the return tonormal difierential being automatic.

This present invention is an improvement on the subject matter ofapplication Serial N o. 731,- 774 filed June 21, 1934. 7

What I claim as my invention is:

1. The combination with a difierential gear including alined axles and arotatable difierential case of a positive clutch whereby one of theaxles may be locked to the dififerential case; and clutch operatingmechanism including a spring tending to move the clutch to the lockingposition, a stronger spring normally neutralizing the first mentionedspring and manually operable means for inhibiting the effect of the saidstronger 5 spring.

2. The combination with a differential gear including alined axles and arotatable differential case of a positive clutch whereby one of theaxles may be locked to the differential case; and clutch 10 operatingmechanism including a crank shaft formed with a crank arm, a springconnected to a stationary part and the crank arm tending to move theclutch to the locking position, a wire connected to the rock arm adaptedwhen sufill5 ciently tensioned to rock the said arm to disengage theclutch, a spring engaging the wire and a stationary part adapted toapply suificient tension to the wire to disengage the clutch against theaction of the first mentioned spring, the wire 20 'being provided withmeans whereby it may be manually moved against the pressure of thesecond mentioned spring.

3. The combination with a difierential gear including alined axles and arotatable difierential 25 case of a positive clutch whereby one of theaxles may be locked to the differential case; and clutch operatingmechanism including a spring tending to move the clutch to the lockingposition, a stronger spring normally neutralizing the first mentionedspring and manually operable means for inhibiting the effect of the saidstronger spring, and means for varying the degree of overbalance of theone spring over the other.

4. The combination with a differential gear including alined axles and arotatable difierential case of a positive clutch whereby one of theaxles may be locked to the differential case; and clutch operatingmechanism including a crank shalt formed with a crank arm, a springconnected to a stationary part and the crank arm tending to move theclutch tothe locking position, a wire connected to the rock arm adaptedwhen sufiiw ciently tensioned to rock the said arm to disengage theclutch, a spring engaging the wire and a stationary part adapted toapply suificient tension to the Wire to disengage the clutch against theaction of the first mentioned spring, the wire being provided with meanswhereby it may be manually moved against the pressure of the secondmentioned spring, and means for varying the degree of overbalance of theone spring over the other.

TREDGERT LEE ADAMS.

